This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Glucose metabolism in cats under a variety of dietary conditions is being analyzed as part of a study of obesity. By following isotope labels (carbon-13 and deuterium) and measuring amounts of label at specific atom sites in glucose, one can evaluate different metabolic pathways. The analysis involves preparing and extracting a glucose derivative (1,2-isopropylidene-glucofuranose or 'monoacetone glucose') from plasma, collecting carbon-13 and deuterium NMR spectra of this compound, and measuring relative peak intensities. The data are then analyzed according to published algorithms to identify the source of each atom.